Best strategies to maximize cashflow

[Rick Grimes]

Hello all! I've been hoping that someone has a reasonable solution to this problem. The more properties, the more potential problems. Although appreciation is great, it's speculative so I prefer to focus on generating a lot of cash flow. My criteria deals with small multifamily properties (2 to 4 units) and have been wondering what would be the best strategy to maximize cash flow in each property so one can minimize the amount of properties needed to purchase?

I was just wondering for those who buy and hold, if you have any out of the box or basic but over looked strategies to achieve this?